- In order to monitor banana weevils infesting banana plants a simple eco-friendly banana stem trap technique has been developed. The bunch harvested plant is used for making traps. The stem is cut into 30 cm pieces and it is split into two halves and the each half is considered as trap. The cut portion of the stem is kept on the ground facing the soil. The recommended rate of trap per hectare is 100 nos.
- The cut portion releases plant volatiles which attract the banana corm and stem weevil. The trapped weevils are collected manually daily and killed.
Preparation of stem trap
- The longitudinal split stem traps are swabbed with biocontrol agents like Beauveria bassiana (20 g rice chaffy grains formulation / 3 ml in 100 ml of liquid formulation ) or 15 ml of entomopathogenic nematode , Heterorhabditis indica at 1 x 10 9 IJs per ml. The weevils attracted to the traps due to volatiles and gets infected while walking on the surface and killed after 24 hrs. The advantage over the plain stem trapping is , the trapped weevils need not be collected manually for killing , they will die on their own.
Traps swabbed with bioagents
Entomopathogenic nematode, H.indica
- The fingers are infested by banana rust thrips and affects cosmetiv value of the fruit. In order to get blemishes free fingers, bunch sleeves are recommended to tie on the peduncle at the time of shooting (downwards) before opening of all hands. The bunch sleeve should be tied on the peduncle gently without leaving any space for insect entry and the lower end of the sleeve should be kept open. If polythene bunch sleeve is used the bunch sleeve should have 6 % ventilation.
Bunch sleeved plant, bunches at the time of harvest (golden yellow colour fingers)
- In order to prevent the rust thrips damage on the developing fingers , the other control measure is giving 1 ml of Imidacloprid injection (0.2 ml in 500 ml water) at the time of shooting (upright position) using a disposable syringe.
- The NRCB isolate of Beauveria bassiana was mass produced using rice chaff grains as a substrate. This can be prepared under farm house conditions. The material will be ready by 15 days. 20 g rice chaffy grain formulation is sufficient per longitudinal split banana stem trap. The dose is 800 g per acre.
- Identifed best isolate for the management of banana aphid, Pentalonia nigronervosa and talc powder formulation developed. The recommended rate is 2 g / litre of water with adjuant 1 ml/ litre . 20 ml solution per plant should be directed in between the leaf sheath.
- One of the NRCB best isolate of Beauveria bassiana has been licensed to private company under consultancy for manufacturing liquid formulation and sale to the farming community especially banana weevil management .This is available in the trade name of Beauvericide.
Beauvericide, infected banana stem weevil
- The technology by using 50 per cent N applied through neem cake at 3 and 6 months after planting have exhibited 90 per cent reduction in root-lesion-nematode population with 65 per cent increased in yield in six commercial cultivars of banana compared to control.
- The technology by applying Carbofuran granules @ 40 g/plant or Rugby 10G @ 10g / plant or Caldan 4G @ 10g / plant one at planting and second application at third month after planting successfully control the P. coffeae population and increase the yield significantly in cvs. Nendran, Karpuravalli and Monthan. The cost benefit ratio worked out to be much cheaper in newer nematicide Rugby 10 G and Caldan 4G compared to Carbofuran 3G.
- The technology by using any one of the biocontrol agents Pseudomonas fluorescens, Paecilomyces lilacinus, Verticillium chlamydosporium, V. lecanii, Trichoderma viride, Bacillus subtilis and VAM (Glomus fasciculatum and G.mosseae) @ 25g/plant at 3 and 6 months after planting have successfully controls (90 %) the nematode populations in banana.
- Promising biocontrol agents viz. Paecilomyces lilacinus, Trichoderma viride and T.harzianum were mass multiplied by using banana wastes such as banana leaves, pseudostem and petiole. The results indicated that maximum spore load (CFU) of 1x1021 and 1X1019 was recorded from banana leaves in respect to T. viride and T.harzianum whereas maximum spore load of P. lilacinus (2x1012) was noticed from banana pseudostem.
- Significant reduction in nematode population with enhanced plant growth was recorded in plants treated with VAM and two biocontrol agents(P.lilacinus and T.viride) together than in individual treatment in cv. Ney Poovan under field condition.
- Two promising biocontrol agents viz. Paecilomyces lilacinus and Pseudomonas fluorescens for the management of nematodes in banana were released in the name of NRCB Nemacinus and Nemacens at the Centre for the benefit of banana farming community.
- The technology by using neem formulations such as nimbecidine or juerken or neewin as sucker dip treatment @15 ml/litre water for 30 minutes was developed for the successful management of nematodes in banana.
- Vermicompost and undiluted vermiwash from Marigold and banana leaves composted by Eudrilus eugeniae were the most effective treatment in successfully controlling root-lesion nematode infesting banana in cv.Nendran.
- The varieties Singhlal, Sakkarachayna, Malai Kali, Manik Champa, Madavazhai, Kartobiumtham, Marabale, diploids viz. Kunnan, Gragric sarpara, Narmine, Borkal baista, Elavazhai and Musa ac.ssp.burmanica and triploids viz., Dasaman, Kottavazhai Chirapunji, Kalibow, Amrithapani, Terabun, Thenkadali, Ladan and Ennabenian were found resistant to root-lesion nematode, Pratylenchus coffeae.Among them five Diploids (Kunnan, Borkal baista, Gragric sarpara, Elavazhai and Musa ac.ssp.burmanica) and eight triploids (Dasaman, Chirapunji, Kalibow, Amrithapani, Terabun, Thenkadali, Ladan and Ennabenian) were found resistant to both root-lesion and root-knot nematodes.
- An eco-friendly technology involving neem formulations such as Nimbecidine or Juerken or Neewin as sucker dip treatment @15 ml/litre water for 30 minutes followed by application of biocontrol agents Paecilomyces lilacinus (NRCB Selection) andPseudomonas fluorescens @ 15 g each with Neem cake @ 500 g per plant at 3rd and 6th month after planting with marigold as an intercrop have been developed successfully for the effective control of root-knot and root-lesion nematodes in banana.
- Field evaluation indicated that Carbendazim applied as dipping the suckers + drenching on 2nd, 4th and 6th month after planting + injection at 2nd, 4th and 6th month after planting recorded no incidence of wilt.
- Combined application of rhizospheric and endophytic fungal antagonists viz., endophytic T. harzianum Prr2 + rhizospheric T. harzianum, endophytic Penicillium pinophilum Bc2 + rhizospheric T.koningii, Penicillium sp. Dsr1 + T. koningii, endophytic P. pinophilum Bc2 + rhizospheric T. koningii + difenaconazole 0.1% and endophytic P. pinophilum Bc2 + rhizospheric T. koningii + difenaconazole 0.1% for three times recorded more than 95% of plants came for harvest as against 47.36% in untreated control plants and percent increase in bunch yield was ranged from 48.3 to 74.8 when compared to untreated control plants and the maximum increase in yield was observed in Penicillium sp. Dsr1 + T.koningii applied plants.
- First time reported cross-reaction among race-1 and race-2 isolates of Foc in India. Identified the presence of 9 different VCGs in India. Foc diversity map of India has also been developed.
- The pathogen responsible for causing leaf spot disease in India has been identified morphological and molecular methods as Mycosphaerella eumusae. Molecular markers to differentiate all the three species of Mycoshaerella have also been developed and validated. Diversity analysis carried out showed the presence of three different major groups of M. eumusae isolates in India and each group was further categorized into separate clades showing the presence of wide genetic diversity among the M.eumusae isolates of India. The diversity analysis by the sequence of rDNA-ITS region and by RAPD has clearly distinguished all the three major species of Mycosphaerella viz, eumusae, fijiensis and musicola from each other and indicated the presence of three different major groups of M. eumusae isolates in India. A SCAR marker specific to M. eumusae isolates has been identified
- Spraying the Oil 1% conc.with the half the dose of any one of the fungicides tested (ie. Propiconazole (0.05%), companion (0.05%) Carbendazim 0.05% + calixin 0.05%, carbendazim 0.05 and mancozeb 0.12% in order of preference) gave good control of disease in both Robusta (AAA) and Nendran (AAB) and also increased the yield up to 20%.
- The pathogen of rhizome rot (Erwinia spp.) was isolated and confirmed by Electron microscopy and bio chemical studies. The pathogenicity was confirmed.
- Effective management of Erwinia rot disease in banana was achieved by planting apparently healthy suckers + drenching with Pseudomonas fluorescens 1-2 litres per plant (50g/lit of water at 0th + 2nd +4th +6th month after planting + growing sun hemp in the interspaces for 2- 3times till 5 months after planting or planting of apparently healthy suckers and application bleaching powder 4g/plant at 0th + 1st +2nd +3rd + 4th month after planting + growing sunnhemp in the interspaces for 2- 3 times till 5 months after planting
- First time the disease score of Cigar end rot for the assessment of the effect of control measures has been developed.
- First time the Fusarium wilt incidence in cv.Cavendish (5 to 25%) was observed in Theni district of Tamil Nadu. The Foc strain of cavendish was found belong to inodoratum group and the VCG status is 0124. The pathogen can also attack varieties like Karpuravalli (ABB), Rasthali (AAB), Ney Poovan (AB) and Monthan (ABB).
- New wilt like disease caused by a pathogen belongs to a member of the family Tricholomataceae of the order Basidiomycetes was recorded first time and confirmed by DNA sequencing. The fungicide mancozeb flowable was found superior to other fungicides.
- Viral diseases viz., Banana Bunchy Top (BBTV), Bract Mosaic (BBrMV), Streak (BSV) and Infectious Chlorosis were found present in the entire banana growing areas.
- Complete genome of Banana bunchy top virus (BBTV) infecting Hill Banana (HB-TN isolate) grown in lower Pulney hills, Tamil Nadu State, India was cloned and sequenced. The hill banana isolate of BBTV belongs to South pacific group. Sixteen coat protein (CP) and thirteen replicase genes (Rep) sequences of BBTV isolates collected from different banana growing states of India were cloned and sequenced. Our study revealed that the Indian BBTV isolates with distinct geographical origins belonged to the South Pacific group, except Shervroy and Kodaikanal hill isolates which neither belonged to the South Pacific nor the Asian group.
- Complete genome of two Banana streak virus (BSV) species viz., banana streak Mysore virus – Trichy (BSMysV-TRY) and Banana streak ObinoL’ Ewai virus(BSOLV-TRY) infecting cv. Poovan (Mysore, AAB) was cloned and sequenced. The complete genome of Banana bract mosaic virus (BBrMV) infecting Nendran was cloned and sequenced.
Electron Micrograph View of Major Banana Viruses
Immuno and nucleo based detection techniques developed for virus indexing in the project; A. Detection of CMV using DAC-ELISA with recombinant antiserum raised for expressed cp of CMV; B. NASH with non radioactive probes the detection of BBrMV; C. Dot Immuno Binding Assay for the detection of BBrMV; D. Duplex and Multiplex Reverse transcriptase PCR for simultaneous detection of more than one virus
- Coat proteins of BBTV, BBrMV, BSMYV and CMV were expressed in bacterial system and produced polyclonal antiserum for BBrMV and CMV diagnosis. Multiplex RT-PCR has been developed for the simultaneous detection of episomal BSMysV and BBTV. Multiplex Reverse Transcriptase PCR has also been standardized for the four banana viruses which included BBTV and BSMYV (DNA viruses). PCR based protocols have been developed to detect viruses in vectors. Real time PCR technique for detection of BBTV using TaqMan probes and SYBR GREEN has been standardized.
- Management strategy for BBrMV has been developed by increased application of fertilizer dose (25-50% of more than the recommended dose) in plant crop of cv. Poovan, Ney Poovan, Robusta, and Nendran bananas.
- To eradicate the BBTV in Hills, virus free plants of Virupakshi were developed, maintained at NRCB farm and supplied to farmers.
- Banana germplasm conserved in the field gene bank at different locations (AICRP centres, NRCB) and in vitro gene bank of NBPGR are being indexed.
- Virus indexing in banana has been disseminated by conducting five national level trainings, consultancy projects and contract services.
- Fluorescent Insitu Hybridization (FISH), a technique to locate endogenous pararetroviral sequences (EPRV’s) of BSV in banana and plantain has been standardized in cv. Poovan and other ‘B’ genome harboring clones.
- Developed RNAi hairpin construct derived from sense replicase gene of BBTV along with antisense truncated rep fragment.
- Developed multivirus RNAi construct for BBTV, CMV and BBrMV for the use in developing transgenic banana
- Virus responsive microRNAs were amplified using primers designed based on the computational prediction.
- Integration pattern of BSOLV in the chromosome of different banana cultivars revealed that the pattern is different in some cultivars.
- Developed 11 putative transgenic lines of transgenic Hill banana through Agrobacterium mediated genetic transformation using replicase gene of BBTV as transgene to get virus resistant transgenic Hill Banana resistant to BBTV
- Developed BSMysV and BBTV-IG3 promoters derived from banana viral genome